Has anyone tried the CSP2/Taboo combo on lower efficiecny speakers? I know the recommendation is for 90dB or higher, but I have a pair of speakers I love that I don't want to change. At the same time, I would like to try the Taboo with my existing CSP2.

Well, freight there and back and a restocking fee can make this a not insignificant trial. 89 db is not the same as 86 db. No offense to anyone here, but I recommend calling Steve, his is the most valuable opinion. He'll know.